1. Field of the Invention
The present invention relates to a liquid level detector for detecting a level of a liquid stored in a container. More particularly, the present invention relates to a non-contact type liquid level detector in which a magnetoelectric conversion element is used.
2. Description of the Related Art
This type liquid level detector is used, for example, for monitoring the amount of fuel accommodated in a fuel tank of an automobile.
For example, this type liquid level detector includes: a float which floats on liquid, the level of which is an object to be measured; a magnet holder for holding a magnet and having a hole portion; an arm for connecting the float with the magnet holder so that a vertical motion of the float can be converted into a rotary motion of the magnet holder; a main body portion having a shaft portion, for pivotally holding the magnet holder so that the magnet holder can be freely rotated around the shaft portion when the shaft portion is engaged in the hole portion; and a magnetoelectric conversion element fixed to the main body portion so that the magnetoelectric conversion element can cross a magnetic flux of the magnet, wherein a rotary angle of the magnet holder, that is, a liquid level is detected when a magnetic flux density of the magnet, which crosses the magnetoelectric conversion element, is detected by the magnetoelectric conversion element (Refer to Japanese Patent Publication No. 2002-206959).
In general, this type liquid level detector includes a regulating means for regulating a rotary angle range of the arm. Usually, a pair of regulating means are provided on both end sides of the rotary angle range of the arm. This regulating means includes a main body portion for pivotally holding a magnet holder and having a magnetoelectric conversion element. In the conventional liquid level detector described above, a flange for preventing the arm from coming out fulfills this function.
In this connection, the profile of a container, to which the liquid level detector is attached, varies, that is, the profile of a fuel tank of an automobile varies. Further, the range of fluctuation of a liquid level to be detected varies, that is, the range of fluctuation of a liquid level is changed from a state in which the fuel tank is filled with petrol to a state in which the fuel tank is empty.
In the liquid level detector, in order to cope with a plurality of types of ranges of liquid level detection, at least one of the arm length, that is, the radius of gyration of the float and the rotary angle range of the arm is adjusted.
Recently, the profile of a fuel tank of an automobile has become complicated. Therefore, the selection of the radius of gyration of the float is restricted. For the above reason, mainly, the rotary angle range of the arm is appropriately set according to the fluctuation range of the liquid level to be detected. In other words, it becomes necessary to provide many types of main body portions in which a position where the regulating means for regulating a rotary angle range of the arm is arranged is changed.
In general, the main body portion is made of resin, and the pair of regulating means described above are molded integrally with the main body portion. Accordingly, in order to set the regulating means at a plurality of positions, it becomes necessary to manufacture a plurality of molds for molding the main body portion. Due to the foregoing, problems are caused in which the manufacturing cost of the liquid level detector is increased.